This application is directed to a method and apparatus for controlling the growth of kudzu, more specifically to the use and deployment of barriers for limiting the range of growth of the kudzu vine.
Kudzu (Pueraria Spp.) was introduced in the United States in 1876 at the Centennial Exposition at Philadelphia, Pa. In the 1920""s it was discovered that animals would eat the plant and it was promoted as forage at that time. In the 1930""s, the Soil Conservation Service promoted the use of kudzu for erosion control. Since that time, kudzu has spread and been utilized all over the southeast portion of the United States.
Kudzu is a non-native trifoliate-leafed, semi-woody climbing vine. The vines are capable of going up to 60 feet in a single season with as much as one foot per day during early summer. The starchy, tuberous root can reach a depth of 12 feet and weigh between 200 to 300 pounds. Vines spread growing from a root crown and will root every few feet at the nodes forming a new plant. Mature stands may have a plant every one to two feet and one acre can easily contain tens of thousands of plants.
While primarily a problem in the southeastern United States, kudzu has spread to the northeast and midwestern regions as well. It is estimated that over seven millions of acres have been ensnared by this plant and it is roughly spreading at the rate of 120,000 acres per year at an exponentially increasing rate. It has infected millions of acres of farmland, forest land, highway and utility right of ways in small cities, large metropolitan and suburban areas.
There are four conventional methods of controlling kudzu. Herbicides can kill the vegetation, but it has been discovered that repeated treatments are necessary to eradicate kudzu. Often up to five, if not ten years, of repeated treatment is necessary. Herbicides may not be particularly environmentally friendly and/or may be relatively expensive.
Grazing animals will readily eat kudzu foliage. Overgrazing is a possible treatment when the grazing animals are fenced within an area of kudzu. Unfortunately, if any of the kudzu extends beyond the boundary of the fenced areas, as soon as the animals are removed, the infestation typically begins anew.
Mechanical removal may be utilized, but it is preferred to remove the roots. While mowing, weeding or other mechanical removal techniques can provide a landowner with immediate satisfaction, if the roots are not removed, the growth will emerge back into the control area.
Finally, prescribed burning will weaken the roots by consuming the foliage, however, burning is a dangerous technique since the fire must be controlled. Furthermore, repeated burning will be necessary.
Accordingly, a need exists to control kudzu in a selected area and/or once kudzu infestation has occurred, selectively preventing kudzu reinfestation into selected areas.
In one embodiment of the present invention, a guard is placed about a tree, utility poles, and/or guy wires supporting utility poles. It has been discovered that kudzu can grow up to slightly less than about four feet unsupported in a vertical or horizontal direction. Once the vine achieves this approximate critical distance, the weight of the vine is acted on by gravity to pull the stalk back down towards the ground if the stalk has not securely attached itself to a structure such as a tree or otherwise.
The guard provides a barrier in the form of a smooth vertical surface which prevents the vine from continuing vertical growth since as the vine attempts to wrap itself around the guard, it reaches a critical length before the vine has solidified enough to form a supporting base to continue upward growth. A predetermined circumference length has been found necessary to prevent attachment to the guard. Accordingly, as the vine attempts to wrap around and climb up, as it reaches a certain length, the weight of the vine causes it to fall away from the guard. The guard""s smooth surface acts in harmony with the kudzu plant""s limited unsupported vertical reach characteristic. Accordingly, the kudzu is unable to pass the barrier and continue its upward climb. The guard has effectively stopped the progress of the vine.
Plastic sheets may also be utilized to prevent horizontal movement of the plant past a desired point. Since the vines only spread on top of the ground, the sheets may be placed in the path of the kudzu and as long as the sheets extend above the predetermined height and down to the ground, the kudzu will be unable to climb under or up and over the sheets. It is important that the sheets extend down to the ground since any openings through the sheet will provide an opportunity for the kudzu to pass through and/or support continued growth up and over the sheets. The sheets may be combined with a fence for support so that the fence prevents advancing kudzu from infesting a particular area.
Another embodiment of the invention is a flag design which prevents the kudzu vine from completing a wrap about the flag as it attempts to climb up a guy wire or other structure. Once again, the flag must have a certain length and width combination so that the kudzu cannot unsupportedly climb from one end of the flag to the other therefore bypassing the flag.